Question

我有一个人们正在使用的应用程序，有些用户遇到了错误我已经想到当我尝试从Coredata读取时它返回空值。

我已经做了一些阅读，发现coredata会给你一些棘手的东西，它只会在你需要的时候返回数据，从我读到的这个叫做断层或其他东西。有趣的是，这个错误不会发生在每个设备上。我认为它取决于内存或某些东西，它可以选择操作系统。

这是我用来读取coredata以及我的堆栈跟踪的代码。

- (NSMutableArray *)readManuf
{
    NSManagedObjectContext *context = [self managedObjectContext];

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    [fetchRequest setReturnsObjectsAsFaults:NO]; // added to fix fault, but not working.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Manuf" inManagedObjectContext:context];
    [fetchRequest setEntity:entity];

    [fetchRequest setReturnsObjectsAsFaults:NO];

    NSError *error = nil;

    NSMutableArray *manufacturerDictionaryArray = [[NSMutableArray alloc] init];

    NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
    for (Manuf *manuf in fetchedObjects) {

        NSMutableDictionary *tempManufacturerDictionary = [[ NSMutableDictionary alloc] init];

        [tempManufacturerDictionary setObject:manuf.hasModel forKey:@"HASMODEL"]; // error app calls over
        [tempManufacturerDictionary setObject:manuf.isManufacturer forKey:@"ISMANUFACTURER"];
        [tempManufacturerDictionary setObject:manuf.nicknames forKey:@"NICKNAMES"];
        [tempManufacturerDictionary setObject:manuf.manufacturer forKey:@"MANUFACTURER"];
        [tempManufacturerDictionary setObject:manuf.manufacturerID forKey:@"MANUFACTURERID"];

        [manufacturerDictionaryArray addObject:tempManufacturerDictionary];
    }
    return manufacturerDictionaryArray;
}

继承我的堆栈跟踪。

<_NSCallStackArray 0x155f6790>(
0   ???                                 0x0323d714 0x0 + 52680468,
1   CodeI                               0x00059ba9 main + 0,
2   CoreFoundation                      0x306488f3 <redacted> + 818,
3   CodeI                               0x000d83eb -[CoreDataController readManuf] + 1134,
4   CodeI                               0x0008c4cb -[EngineRequests GetManufacturers:CallingView:] + 806,
5   CodeI                               0x00076ddf -[VehicleSearchViewController tableView:cellForRowAtIndexPath:] + 1278,
6   UIKit                               0x3305c8f7 <redacted> + 410,
7   UIKit                               0x33003c27 <redacted> + 1806,
8   UIKit                               0x3300347d <redacted> + 184,
9   UIKit                               0x32f29d59 <redacted> + 380,
10  QuartzCore                          0x32ba762b <redacted> + 142,
11  QuartzCore                          0x32ba2e3b <redacted> + 350,
12  QuartzCore                          0x32ba2ccd <redacted> + 16,
13  QuartzCore                          0x32ba26df <redacted> + 230,
14  QuartzCore                          0x32ba24ef <redacted> + 314,
15  UIKit                               0x32f2d3e1 <redacted> + 8232,
16  CoreFoundation                      0x306d820b <redacted> + 14,
17  CoreFoundation                      0x306d76db <redacted> + 206,
18  CoreFoundation                      0x306d5ecf <redacted> + 622,
19  CoreFoundation                      0x30640ebf CFRunLoopRunSpecific + 522,
20  CoreFoundation                      0x30640ca3 CFRunLoopRunInMode + 106,
21  GraphicsServices                    0x35546663 GSEventRunModal + 138,
22  UIKit                               0x32f8d14d UIApplicationMain + 1136,
23  CodeI                               0x00059c1d main + 116,
24  libdyld.dylib                       0x3b39dab7 <redacted> + 2
)

因为我已经阅读了一篇文章，其中说过将对象放入像我这样的字典NSArray中会导致错误，因为当coredata尝试填充数组时，它需要在其原生对象中。

所以我已经将我的读取方法改为此。

- (NSArray *)readManuf
{
    NSManagedObjectContext *context = [self managedObjectContext];

    // Test listing all FailedBankInfos from the store
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    [fetchRequest setReturnsObjectsAsFaults:NO];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Manuf" inManagedObjectContext:context];
    [fetchRequest setEntity:entity];

    [fetchRequest setReturnsObjectsAsFaults:NO];

    NSError *error = nil;


    NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];

    return fetchedObjects;
}

返回本机对象的MutableArray。但是，当我尝试使用这个本机对象数组时，它仍然不会在任何时候填充。

CoreData读取错误，空值导致错误

0 个答案: